Remove Alias Apple ID Email
How do I remove an "alias" email that is associated with my Apple ID?
For example, let's pretend my Apple ID is: Example@gmail.com. When I go into my account settings or to manage my settings there is an alias email address associated with it called: JoeBlowExample@icloud.com. I am not JoeBlow, and have no access to that iCloud.com account. How do I remove it as an alias? I can add other email addresses that are associated with me, but that alias address cannot be removed. Other associated accounts have an "x" beside them, but this has a "?". When I hover over the question mark is says "This is an Alias of your Apple ID email address." (See Picture embedded)
It probably wouldn't be such a big deal, but somehow that is the default email address on my new phone. (An iPhone 8) Since I don't have access to that email, I don't want confidential emails to accidentally be "replied" to at that iCloud address.
iPhone 8